Growth and Properties of CNx Films Prepared by Reactive DC Magnetron Sputtering

Carbon nitride (CN x ) films have been deposited by reactive sputtering of a graphite target with nitrogen and/or argon gases. A modified cylindrical DC magnetron was used as a sputter deposition source and the processing plasma was monitored by means of both a Langmuir probe and optical emission spectroscopy (OES). The nitrogen to carbon ratio (N/C ratio) evaluated by X-ray photoelectron spectroscopy (XPS) ranged from 0 to 0.5. Strong correlation between N/C ratio in the film and N 2 + /N 2 * emission intensity ratio was confirmed from the result of the OES study. An absorption band near 2200 cm -1 in the Fourier transform infrared (FT-IR) spectra strongly indicated the existence of C≡N covalent bonding. Transmission electron microscopy (TEM) bright-field imaging revealed that the prepared CN x film contained nanocrystallines buried in the amorphous background and the observed grain size was 10–60 nm range.